@SupaPhly part of the reason could be that they are more responsive to FOREX fluctuations than MS or Valve. The other reason is that we are so small for Sony that they can't be bothered to match what happens on the other platforms.
If you have both consoles it allows you to price shop, i've picked up a few games this way.
Minecraft: Story Mode - A Telltale Game Series The Complete Adventure
Minecraft: Story Mode is an all-new narrative-driven game series developed by Telltale in collaboration with Mojang. Set in the world of Minecraft, the series features an original story, driven by player choice.
Telltale's game series will mix new characters with familiar themes, in an entirely original Minecraft experience, inspired by the Minecraft community and the game that continues to inspire a generation.